Acoustic Radiation Force Impulse Elastography for Efficacy Evaluation after Hepatocellular Carcinoma Radiofrequency Ablation: A Comparative Study with Contrast-Enhanced Ultrasound

Abstract

Aim. To explore acoustic radiation force impulse (ARFI) elastography in assessing residual tumors of hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA). Materials and Methods. There were 83 HCC lesions among 72 patients. All patients were examined with ARFI, contrast enhanced ultrasound (CEUS), and CT or MRI. Tumor brightness on virtual touch tissue imaging (VTI) and shear wave velocity (SWV) were assessed before and approximately one month after RFA. Results. There were 14 residual tumors after RFA. VTI showed that all the tumors were darker after RFA. VTI was not able to distinguish the ablated lesions and the residual tumors. 13 residual tumor lesions were detected by CEUS. All completely ablated nodules had SWV demonstration of x.xx., while with those residual nodules, 6 tumors had x.xx measurement and 8 tumors had measurable SWV. nine lesions with residual tumors occurred in cirrhosis subjects and 5 lesions with residual tumors occurred in fibrosis subjects; there was no residual tumor in the normal liver subjects. Conclusion. VTI technique cannot demonstrate residual tumor post RFA. While SWV measurement of less than x.xx is likely associated with residual tumors, measurement of less than x.xx cannot exclude residual tumors. Liver cirrhosis is associated with decreased chance of a complete ablation.

Ultrasound-guided percutaneous microwave ablation for benign breast lesions: evaluated by contrast-enhanced ultrasound combined with magnetic resonance imaging

“…Image-guided nonsurgical ablative therapies, including radiofrequency, MWA and high-intensity focused US have received increasing attention as minimally invasive treatments to destroy various solid tumors. The breast is the perfect organ for ablation because the breast locates in superficial location, cover only by skin with no intervening structures, can be compressed asymmetrically to achieve ablation strategy and monitored effectively by US (6). MWA is a promising minimally invasive local therapy with many advantages, including large ablation zones, short ablation durations, and improved convection profile (7)(8)(9).…”

“…MRI is the most optimal modality for visually describing the tumor volume and for evaluating the ablative efficacy. In recent years, several ablation techniques, including radiofrequency ablation (RFA), laser ablation, cryoablation and microwave ablation (MWA) have been evaluated in clinical trials (2)(3)(4)(5)(6). Compared with others ablation techniques, MWA is a promising technique because it can preferentially heat and damage high-watercontent breast tumors, whereas the lesser degrees of heating lower-water-content fatty and glandular tissues.…”

Increased matrix stiffness promotes tumor progression of residual hepatocellular carcinoma after insufficient heat treatment

“…In our previous work, we showed that higher matrix stiffness increases vascular endothelial growth factor and osteopontin secretion and stem‐like characteristics to promote HCC progression . Radiofrequency ablation ablates the tumor and leads to dramatic changes in the mechanical properties of the tumor environment, that is, it further increases the local tissue stiffness . In this study, we showed that increased matrix stiffness promotes the progression of heat‐treated residual HCC cells, which will help to explain accelerated disease progression after incomplete RFA.…”

“…However, RFA not only destroys the tumor, but also alters the biomechanical environment drastically. Similar to the increased tissue stiffness induced by cardiac RFA, a significant increase in tissue stiffness at the ablated site after liver RFA has been detected by elastography techniques . The potential role of the changed physical attribute of the microenvironment induced by thermal ablation on the malignant behaviors of residual HCC has not been addressed.…”

“…Similar to the increased tissue stiffness induced by cardiac RFA, (15) a significant increase in tissue stiffness at the ablated site after liver RFA has been detected by elastography techniques. (16,17) The potential role of the changed physical attribute of the microenvironment induced by thermal ablation on the malignant behaviors of residual HCC has not been addressed. Given that increase in liver stiffness can favor tumor development, (18)(19)(20) it is reasonable to hypothesize that increased matrix stiffness after RFA, which may constitute the mechanical property of the cancer cell niche, could promote the progression of residual tumor after insufficient RFA.…”